Key parameters at a glance

A radius of 1.77 Earth radii
A mass of 9.70 Earth masses
Surface gravity around 3.09 g
An orbital period of 3.696 days
Semi-major axis 0.0457 AU
Equilibrium temperature 1,187 K (914 °C)
Distance from Earth 921.60 light-years
Earth Similarity Index 0.217
Travel time at Voyager 1 speed 16,252,348 years

5 siblings around Kepler-20

Kepler-20 b shares its host star with 5 other confirmed planets. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
Kepler-20 b this	Super-Earth	1.77	9.70	3.696	1,187	2011
Kepler-20 e	Rocky Terrestrial	0.82	0.76	6.098	1,004	2011
Kepler-20 c	Sub-Neptune	2.89	11.10	10.854	828	2011
Kepler-20 f	Rocky Terrestrial	0.95	1.40	19.578	681	2011
Kepler-20 g	Neptune-like	4.71	19.96	34.940	524	2016
Kepler-20 d	Sub-Neptune	2.61	13.40	77.611	430	2011

Kepler-20 b Planet Profile

Physical Specs

Radius

1.77 R⊕

Radius (Jupiter)

0.158 R♃

Mass

9.70 M⊕

Mass (Jupiter)

0.031 M♃

Density

9.40 g/cm³

Surface Gravity

3.09 g (Earth)

Classification

Planet Type

Super-Earth

ESI Score 0.217

HZ Position Inner

Controversial No

Discovery

Year 2011

Method Transit

Facility Kepler

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#292of 1176

top 24.7%

This planet

1.77R⊕

Super-Earth median

1.60R⊕

Nearest-size peers

GJ 667 C c 1.77 R⊕ Kepler-286 e 1.77 R⊕ Kepler-215 c 1.77 R⊕

Metric	Earth	Kepler-20 b	Jupiter
Radius (R⊕)	1.00	1.77	11.21
Mass (M⊕)	1.00	9.70	317.83
Density (g/cm³)	5.51	9.40	1.33
Surface Gravity (g)	1.00	3.09	2.53
Insolation (S⊕)	1.00	331.00	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	9.700 M⊕	Direct mass measurement (not derived).
Minimum mass (M sin i)	9.513 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

TIC

TIC 158554588

Gaia DR2

Gaia DR2 2102548708017562112

Gaia DR3

Gaia DR3 2102548708017562112

System

Kepler-20

Percentile among Super-Earth cohort

Radius 1.773 R⊕ · percentile 75 / cohort 1176

Mass 9.700 M⊕ · percentile 96 / cohort 1176

Orbital period 3.70 d · percentile 28 / cohort 1164

Distance 282.56 pc · percentile 30 / cohort 1171

ESI 0.217 · percentile 16 / cohort 1176

Orbit & Habitability

Orbital Dynamics

Period

3.696 days

Semi-major axis

0.0457 AU

Eccentricity

0.083

Inclination

87.36 °

Year Length

A year here lasts approximately 3.70 Earth days (1.0% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0457 AU.

Transit Fingerprint

Depth

0.040 %

Duration

2.463 h

Impact parameter b

0.633

Rp / R★

0.019250

Transit midpoint (BJD)

2,454,967.5023

Photometric dip

Transit produces a flux drop of 397 ppm lasting ≈ 2.46 h.

Extended Orbital Architecture

Planet / star radius ratio

0.019250

Semi-major axis / stellar radius

10.340

Impact parameter (b)

0.633

RV semi-amplitude (K)

4.230 m/s

Transit mid-time (BJD)

2,454,967.5023

Angular separation (arcsec)

0.16200

Eq. Temperature

1,187K

(914 °C)

Insolation (S⊕)

331.00

Earth = 1.00

Earth Similarity (ESI)

0.217

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched.

Detection Signatures

Transit photometry

A transit dip has been observed from at least one telescope.

Radial velocity

Stellar wobble has been measured spectroscopically.

Discovery Paper

Primary reference

Gautier et al. 2011

Instrument

Kepler CCD Array

Publication

2012-04

Observation locale

Space

Discovery cohort

Planets confirmed in 2011 at Kepler (12 shown).

Kepler-22 b · Sub-Neptune Kepler-20 d · Sub-Neptune Kepler-26 c · Sub-Neptune Kepler-19 c · Sub-Neptune Kepler-26 b · Sub-Neptune Kepler-28 c · Super-Earth Kepler-10 c · Sub-Neptune Kepler-20 f · Rocky Terrestrial Kepler-42 d · Rocky Terrestrial Kepler-16 b · Neptune-like Kepler-28 b · Super-Earth Kepler-34 b · Neptune-like

Host System: Kepler-20

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,495 K — cooler than the Sun (5,778 K)

Estimated Age

5.60 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.916 R☉

Stellar Mass

0.929 M☉

Metallicity [Fe/H]

0.07

Extended Stellar Properties

Surface gravity (log g)

4.446 dex

Stellar density

1.360 g/cm³

Systemic radial velocity

-20.93 km/s

Rotational v·sin i

0.40 km/s

Metallicity ratio

[Fe/H]

Distance

282.56 parsec

Light-years 921.60 ly

V-band magnitude

12.61 mag

Voyager-speed travel 16,252,348 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

3.510 mas

Total Proper Motion

27.251 mas/yr

PM Right Ascension

-3.98 mas/yr

PM Declination

-26.96 mas/yr

Galactic Cartesian (pc)

x = 0.225 · y = -0.704 · z = 0.674

Equatorial (J2000)

RA 287.69799° · Dec 42.33858°

Galactic ℓ, b

73.377° · 14.573°

Ecliptic λ, β

300.714° · 63.902°

HTM-20 index

-1933436408